The present invention relates to an open showcase having a front opening formed for putting in and taking out goods and closed with a cooling air flow and a protection air flow.
Conventionally, this type of an open showcase comprises, as shown in Japanese Patent Application Laid-open No. 5-306871, a heat insulating wall, an inner wall in the heat insulating wall, and a partition wall to form an outer layer duct where the protection air flows and an inner layer duct where the cooling air flows, so that the protection air and the cooling air blow out from their respective outlets formed in the upper edge of the opening of the heat insulating wall to the front opening of the heat insulating wall so as to generate a protection air curtain formed with the protection air flow and a cooling air curtain formed with the cooling air flow, by which the front opening is closed.
The inner layer duct is provided with a cooler which cools down the cooling air in the inner layer duct to a predetermined temperature. Thus, the cooling air blown out from the outlet prevents the outer air from entering through the opening and at the same time cools down the display room. On the other hand, the outer layer duct is not provided with a cooler, but the protection air curtain formed with the protection air is positioned outside of the cooling air curtain formed with the cooling air, and protects the cooling air curtain while preventing the outer air from entering the display room.
Referring to FIG. 4, a conventional open showcase 100 is explained below. FIG. 4 is an enlarged longitudinal cross sectional side view of the top edge portion of an opening 109 of the conventional open showcase 100. A heat insulating wall 101 opened at its front is provided, and a partition wall 102 is provided inside the heat insulating wall 101 to form an outer layer duct 103 between the heat insulating wall 101 and the partition wall 102. An inner wall 104 is provided inside the partition wall 102 to form an inner layer duct 106 between the partition wall 102 and the inner wall 104.
The inner layer duct 104 is provided with a cooler and an air blower and the cooling air passing through the cooler flows therethrough. The outer layer duct 103 is not provided with a cooler and is provided with an air blower only, and the protection air blows therethrough. The heat insulating wall 101 has an outer layer outlet 107 formed at the front side of the top edge of the opening and the outer layer outlet 107 communicates with the outer layer duct 103. An inner layer outlet 108 is formed at the back of the outer layer outlet 107 and the inner layer outlet 108 communicates with the inner layer duct 106. To the outlets 107 and 108, honeycomb materials for air blow arrangement (not shown) are mounted.
Thus, the cooling air in the inner layer duct 106 blows out of the inner layer outlet 108 and forms the inner cooling air curtain and the protection air in the outer layer duct 103 blows out of the outer layer outlet 107 and forms the outer protection air curtain. Thus, a dual air curtain is formed at the front opening of the heat insulating wall 101.
The outlets 107 and 107 above are partitioned to the front part and the back part with a partitioning member 110. The lower front part of the partitioning member 110 is formed with an inclination inward and serves as an arrangement plate to direct the protection air from the outer layer outlet 107 inward or toward the display room.
In the above-mentioned case, the partitioning member 110 partitioning the outlets 107 and 108 is applied to the bottom of the front part 102A of the partition wall 102 and fixed with a screw 111. However, the front part 102A of the partition wall 102 may be wavy due to poor forming or deformation in the assembly process. In particular, the partition wall 102 is formed with a single steel plate material longitudinally from the right to the left of the front opening and is vulnerable to deformation during the assembly process. There is a drawback that a gap may be formed between the partitioning member 101 and the front part 102A of the partition wall 102.
Therefore, there is a drawback that the cooling air rising in the inner layer duct 106 may leak out of the gap between the front part 102A of the partition wall 102 and the partitioning member 110 to the outer layer duct 103. With the cooling air flowing toward the outer layer duct 103, the cooling air blown out of the inner layer outlet 108 decreases and the cooling air curtain is disturbed. This causes improper closing of the front opening of the display room with the cooling air curtain. The display room may be cooled poorly or cooling of the front face of the partitioning member 110 may result in dewing.
To settle the above-mentioned drawbacks, a sealer 112 is applied between the partitioning member 110 and the bottom of the front part 102A of the partition wall 102 as shown in FIG. 5 in the conventional showcase. However, this cannot effectively close the gap formed between the partition wall 102 and the partitioning board 110 and the cooling air rising in the inner layer duct 106 leaks out toward the outer layer duct 103 from the gap between the front part 102A of the partition wall 102 and the partitioning member 110.
Therefore, in case of an open showcase disclosed in the patent document 1, the partitioning member 110 is provided with a heater to suppress dewing occurring at the front of the partitioning member 110 when it is cooled by the cooling air leaking out of the gap.
With this configuration, a heating means is provided at the cooling air blowing part and there are problems of heat efficiency and complicated wiring connection. Furthermore, increase in the number of parts results in a higher cost.